Power-driven hand unit for rotary and reciprocating tools



Nov. 4, 1958 F. P. WILLCOX ,3 03

POWER-DRIVEN HAND UNIT F OR ROTARY r AND REK'HIPROCATIIING TOOLS Filed June 29, 1955 1 l? Will/cox,

IN V EN TOR.

A rice/v6? llnited States Patent POWER-DRIVEN HAND UNIT FOR ROTARY AND RECIPROCATING TOOLS Frederick P. Willcox, Old Westbury, N. Y. Application June 29, 1955, Serial No. 518,808 3 Claims. (Cl. 7444) This invention pertains to an electrically powered tool which will provide the mechanic, jeweler, model maker and others with a compact and light weight device by which a variety of material working operations can be accomplished conveniently and efficiently. More specifically, the invention aims to provide a power driven hand tool suitable for driving bits, saws, files and similar implements to perform a wide variety of cutting and shaping operations in metal, plastic or the like, by imparting either rotary or reciprocating motion to an implement, or simultaneously providing both rotary and reciprocating motions.

In accordance with a preferred embodiment of the invention, the basic unit includes two chucks or implement holders, one providing a rotary motion output and the other a reciprocating motion output, and such that the working stroke of the reciprocating output can be adjusted smoothly and continuously over its entire range of strokes.

The invention further provides a compact multi-purpose tool of the above kindwhich uses only a single motor to obtain both kinds of motions, and in which certain parts of the linkage or connections between the motor and the output devices (chuck or chucks) are common to both kinds of motive outputs. The satisfaction of this object permits a great flexibility in selecting the kind of drive employed for the material working implement, without adversely increasing the size, weight or cost of the entire unit. Thus, a unit according to the invention permits such diverse operations as drilling, rotary grinding, reciprocating grinding, rotary and reciprocating filing, and rotary and reciprocating sawing, as well as other special operations that will be apparent to the skilled user of the device.

A preferred embodiment of the invention will now be described in detail, by way of example, in connection with the appended drawings, in which:

Fig. l is a side elevation of a preferred form of the invention, in which separate tool holders are provided for rotary and reciprocating motions, one being substantially axial with the casing and the other having an axis displaced to one side of the casing.

Fig. 2 is a diagrammatic view partly in perspective of the internal parts of the invention, and

Fig. 3 is a fragmentary perspective exploded view, partly in section, the section being taken on line 33 of Fig. 2.

Referring now to the drawings, and first to Fig. l thereof, the major body of the device comprises a casing containing a rotary motor, whose shaft drives directly a chuck or tool holder 12 which therefore undergoes rotation only. Casing 10 includes brush holders (one indicated at 14), ventilating slots 16 and end covers 18 and 20. Cover 18 adjacent chuck 12 is preferably knurled as at 22 for a convenient hand grip. The axis of rotation of chuck 12 will desirably lie along the central axis of the motor. A separate drive transmission imparts reciprocative motion to a second tool holder 24 extending out from the opposite end cover 20 of the motor casing,

and for economy of design as well as for operative convenience in close working spaces, the axis of this holder may lie displaced from, the motor axis adjacent the outer wall of the main casing 10. The general layout of parts is indicated schematically in Fig. 2, 26 designating the motor armature rotating in the field structure 28, the electrical circuit including a; speed control rheostat 30.

The motor shaft 32 carries, a worm 34 meshing with a worm wheel 36 coupled to a wheelv 38. Wheels 36 and 38 may actually be made of a single piece, or they may be connected by a shaft such as- 40. In any event, eccentrically pivoted to wheel 38 is the link 42 pivoted to. the reciprocating shaft 44 which leads outside the casing to the tool holder 24, the parts within the casing being indicated as within the dashed casing outline 10. Suitable bearings and guides, carried by the casing, are provided for both shafts.

In order to control the stroke length of tool holder 24, it is only necessary to vary the effective radius at which link 42 is connected to wheel 38. This could be accomplished by providing a series of pivot holes in the wheel 38 at difierent radii, but a continuous variation of effective radius can be achieved by the means shown in Fig. 3. In that figure, wheel 38 carries a pin 46 which is olfcenter with respect to the wheel. Journalled on this pin is an eccentric collar 48, so that the angular position of pin 46 and collar 48 determines the degree of eccentricity, with respect to the axis of wheel 38, of the outer cylindrical surface of collar 48. This angular relation is fixed, when properly set, by clamping collar 48 against wheel 38 as by a screw 50 passing through the collar and threaded into the end of pin 46. Pin 46 may be integral with wheel 38, or may be secured thereto as by a C-ring 52 which snaps into a groove of pin 46 at the rear side of wheel 38. In the latter case, and since the shaft 40 connected to wheel 38 would interfere with the application of the C-ring, the connection between shaft 40 and wheel 38 may be by an enlarged hub on the shaft 40 which is hollowed out to enable the C-ring to be applied or, as shown in Fig. 3, the end of the shaft may be bifurcated as at 54 to provide clearance for the C-ring to be slipped over the end of pin 46.

To provide access for adjustment of the position of the pivot center, the casing 10 (Fig. 1) may be provided with an access hole to screw 50, and a suitable cover 56.

In tools of this sort, which are intended to be held in the hand of the user, the production of adequate power without excessive size and relatively high-speed motor, for example one of the universal type which may have a no-load speed of several thousand revolutions per minute. Such speeds are well adapted for rotary tool applications, but of course are far too high for direct reciprocation of such a tool as a file or saw blade. The present design utilizes a worm reduction gearing for the reciprocative drive only, to accomplish two ends; first, a substantial reduction in rotational speed before the rotary motion is converted to a reciprocating motion, without excessive complication of the converting mechanism, and second, the offset arrangement by which the reciprocating bar is disposed adjacent a casing Wall rather than centrally thereof. As has been stated, this offset relation permits working in close spaces and is generally superior when reciprocating tools are employed.

While the invention has been described in detail as to a preferred embodiment, it will be obvious to those skilled in the art that the novel principles of the invention can be carried out with specifically different structures. Hence, the foregoing description is not to be taken as limting the scope of the invention, which is defined in the appended claims.

weight necessitates a single Iclaim:

1. A portable tool comprising a housing, a motor in said housing having a rotary power shaft projecting centrally through one end of said housing, a tool chuck mounted on said shaft outside said housing, a reciprocating bar extending through the opposite end of said housing parallel to but oifset from said power shaft, and adjacent a lateral housing wall, a tool chuck on the outer end of said bar, a speed reduction transmission means within said casing connecting said shaft and said bar to reciprocate the bar upon rotation of said shaft, said transmission means including manually adjustable means for varying the stroke amplitude of said reciprocating bar, through a continuous range of amplitudes.

2. A portable tool in accordance with claim 1 in which the means for adjusting the stroke amplitude of the reciprocating bar includes a variable eccentric.

3. A portable tool in accordance with claim 1 in which said transmission means connecting said central shaft and the reciprocating bar includes an eccentric shaft mounted for adjustment of its eccentricity from without said hous- References Cited in the file of this patent UNITED STATES PATENTS 272,511 Angell Feb. 20, 1883 1,521,359 Costa Dec. 30, 1924 2,138,862 Johnston Dec. 6, 1938 2,526,976 Smith Oct. 24, 1950 

